U are gonna get people answering here that clean their gun after every range trip - to people who only clean the gun 1x a year. So, U will get all types of answers. There is a thread on that topic someplace around here.
EVERYTIME I go shoot, I clean the gun afterwards. Also, about 1x a month, I remove the slide from the frame, and I use a toothbrush to place new oil on the rails of the frame. Oil tends to evaporate over time. While there is still some lubricity that would remain in that area, I still like to do this about 1x a month.
Also, unless I did it w/i a week or two, I also do this real quick right before a trip to the range - so I know I won't have any issues. This takes less than 1 min, though.
If you sweat on a gun - like when you are carrying it - then its probably a good idea to get some oil on a patch, rub down all the metal parts with it, and then get an old range and wipe the oil off.
My XD gets cleaned immediately after a trip to the range or Friday nights while I watch TV if I haven't been to the range that week. There are people that only clean their XDs after a few hundred (or thousand) rounds. Since my XD is my CCW gun, I like to know that it's clean and lubed in case SHTF and I need to depend on the gun. I also think that regular cleaning helps avoid the rust problem that the XDs are prone to.
I clean all the guns I have right after they are used. I make sure everything is lubed, and working the way it's supposed to. I have never knowed a gun to fail from being lubed, but I have seen them fail from not enough lube.
Cleaning after each use wont hurt your pistol,HOWEVER ,NOT cleaning it COULD get you hurt if you need it for defense and it malfunctions from being dirty.......better safe than sorry(or dead) is a good motto, I'll stick to it myself